Apparatus for controlling the flow of refrigerant in refrigerating apparatus



July 25, 1933- T. E. CARPENTER LQEQGQ APPARATUS FOR CONTROLLING THE FLOOF REFRIGERANT IN REFRIGERATING APPARATUS Filed July 9, 1926 cavnewaezeCon/Wm INVENTOR. momasz Carpenter ATTORNEY.

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"Patented July 25, 1933 THOKASE. CARPENTER OF DETROIT, MICHIGAN,ASSIGNOR, BY MESNE ASSIGNMENTS,

OF TWO-THIRIDSTO ISAAC L. RICE, JR.,

0]? NEW YORK, N. Y., AND ONE-THIRD TO:

STUART C. BARNES, 0F DETROIT, MICHIGAN APPARATI IS FOR CONTROLLING THEFLOW OF REFRIGER ANT APIABATP'S' Application filed July 9,1926. SerialNo, 121,301.

This invention relates to a method of and apparatus for controlling theflow of refrigerant in refrigerating apparatus. It has to doparticularly with the'feeding and the control of the flow of therefrigerant into the cooling device of a mechanical refrigeratingsystem.

It is an object of the present invention to provide means positionedbetween the condensing or liquefying apparatus and the cooling unit forrestricting and accurately controlling thefceding of the refrigerant tosuch unit will be of a predetermined rate corresponding to the capacityof the refrigerating apparatus. This novel device not only restricts andcontrols the flow of refrigerant.

but so restricts the flow in such a novel man-' ner that only a simple,compact device is necessary which entirely does away with' ordinaryexpansion valves and float valves such as have been used in the past.

A further object of this invention contemplates the provision of adevice which not only predetermines the flow of the liquid in accordancewith the capacity of the unit, but which also positively feeds therefrigerant to the cooling device in such a manner as to prevent anyback flow of the refrigerant either in a liquefied or a gaseouscondition. A further object of the invention relates to the manner ofrestricting and feeding the refrigerant in order to obtain ahigh'pressure of such refrigerant and obtainin V a uniform flow of therefrigerant wit out the necessity of using a very small orifice of shortlength or, in other words, obtaining uniform predetermined restrictedflow with a minimum ossibility of clogging or stopping of the rerigerant.

Fig. 1 is a fragmentary front elevation partially diagrammaticillustratingthe na ture of, and manner of embodying, my novel device incombination with an automatic re- Fig. 2 is an enlarged detail viewpartly in section, of my novel capillary tube for restricting andcontrolling the flow of refrigerant and also showing one manner ofconnecting the same to the inlet of a cooling unit.

Heretofore, in the refrigerating art, in

regulating and controlling the flow of refrigerant to the coolingdevice, it has been customary to use some form of an'expansion valve orsome form of a float valve for maintaining theflow or level of therefrigerant to and in the; cooling unit. These various types of valveshave been more or less efficient when operating ideally, but on theother hand, these various valves by reason of their complicatedstructure have been-the source of a large amount of service trouble'incommercial domestic mechanical refrigerating units,

The present device obviates all types of valve structures forcontrolling the transmission of the refrigerant to the cooling unit. Itis positive in its action and is extremely compact and simple. Attemptshave .been made in the past to control the flow of refrigerant to thecooling unit and to do away with the use of float valves and expansionvalves by flowing the refrigerant through 11v QREFRIGERATING a verysmall orifice and thus restricting the flowof refrigerant to apredetermined degree. This form of restriction has not proven successfulfor many reasons, one of which is a tendency of such an orifice to eas-'ily clog up and thus make it necessary to stop the entire system untilthe orifice can be removed and cleaned. The present invention relates ina measure to the idea of restricting the flowlof the refrigerant tocontrol its transmission to the cooling chamber, but instead of merelyproviding the plain restricting orifice, I have discovered that byinserting a capillary tube between the condenser supply tube and thecooling unit, that the capillary action of the refrigerant passingthrough this tube will create the required amount of back pressure andresistance to predetermine the rate of flow.

More specifically, my invention relates to the rovision of a capillarytube which, in its p're erred form,,is coiled so as to present a helicalor spiral passageway for the refrigerant. Such a capillary tube isillustrated in Fig.- 2 and may be designated 1. It is preferablypositioned adjacent to the cooling unit vand may be connected to thecooling unit intake by means of a suitable union 2 such as illustratedin Fig. 2. The intakes 3 for conare preferably somewhat larger in.diameter than the diameter of the capillary tube coils,

whereby the refrigerant is caused to expand as it enters the coolingunit. In the drawing, I have diagrammatically illustrated a refrigcrating system wherein: designates a suitable compressor for withdrawingthe evaporated or expanded refrigerant gases from a cooling unit 5. Acondenser 6 is adapted to receive the compressed refrigerant from thecompressor, and to either liquefy or maintain the liquefication of thecompressed refrigerant. The' condensed refrigerant in flowing underpressure from the condenser to the cooling unit passes through thecapillary tube 1 and thus its entrance into the cooling unit isrestricted aiml controlled in a predetermined manner in accordance withthe diameter and length of the coiled capillary tube.

By embodying capillary, action in restricting and feeding therefrigerant to the cooling unit, it is possible to use a. relativelylarge 7 diameter capillary tube corresponding to the,

extremely small orifice as has heretofore been necessary in using aplain restricting orifice. The length of the capillary action and thecapillary tube compensates for and makes up for the relatively largediameter of the tube. In other words, the capillary tube permits of areasonably larger hole and its resistance is created by its length. I e

I have foundthat in a refrigerating unit having a compressor operatingunder average pressures and a cooling unit of average capacityfa. coiledcapillary tube, approximately 36 inches long and .037 inches in;diameter, satisfactorily(controls the flow 0 refrigerant and maintainsthe level of refrigerant in the coolin unit.

The coiled capil ary tube, by reason of .the adds additional resistanceto the how of the refrigerant, and by the capillary action prevents anyback flow of the refrigerant. Each helical coil acts as a littlehydraulic trap and thus aitcts the positive feeding of the refrigeranttowards the cooling unit. It will be understood that this capillary co1l may be varied inlength in accordance w th the capacity of thepfiticular unit in which it is embodied, and in conformity with thepredetermined rate of flow of refrigerant desired. With a certain headpressure or a certain back ppessure and with a predetermined R. P. M. ofthe compressor, it will be I possible to accurately regulate andpredetermine the rate of flow of refrigerant to the cooling unit byutilizing the capillary coil of a, length in accordance with suchpredetermined head pressure and R. P. of the coin pressor. A 4

It will thus be obvious that I have provided an extremely simple,positive acting andelficient device for regulating and accuratelycontrolling admission of refrigerant to the cooling unit of arefrigeratingsystem whereby the level ofthe refrigerant is in such unitmay be maintained approximately constant due to this predeterminedrestriction of the refrigerant by the capillary tube.

It will be understood that where I have referred to the particular aplication of my invention to mechanical re rigerating sys-' tems, thatthe word mechanical has reference to the use of refrigerating systemshaving a compression system operated by means of a pulsating piston typecompressor.

What I claim is: a

1. In a mechanical refrigerating system of the mechanical compressionexpansion flooded type-the combination of a pulsating piston typecompressor, a condenser, a cooling unit, and a single helical coilcapillary tube positioned between the condenser and compressor,condenser and cooling unit as to restrict the flow of refrigerant andmaintain the transmission to the cooling. unit at a predetermined-rate,-said capillary tube connecting with thecooling unit and condenser.

2. In a refrigerating machine of the mechanical compression, floodedtype, the combination ofa compressor, a condenser and an evaporator,pipe connections between the evaporator, compressor and condenser, inthe order named and a single capillary tube be tween the condenser andthe evaporator of such length and diameter as will maintain apredetermined ratio. between the ressures in the condenser andevaporator during the operation of the compressorwhereby a mass .ofliquid is maintained within substantially predetermined limits at alltimesin said evaporator durin normal operation.

. 3..In a re rigerating machine of the me"- chanicalcompressorfloodedtype, the combi nation'of a compressor,a condenser and anevaporator, pipe connections between the evaporator,condenser andcompressor in the order named, and .a single capillary tube,- said tubebeing located between the condenser and the evaporator and of suchlength and diameter as will maintain a predeterminedratio between thepressures in the condenser and evaporator during theoperation of thecompressor and minimize any tendency of the tube to clog, the said partsof the refrigcrating machine and the refrigerant charge being soco-ordinated that the single capillary tube is adapted to function asthe regulating device of the flow between the condenser and theevaporator and by reason ofthe said co-ordination the liquid'level inthe evaporator is maintained between narrow limits. g

THOMAS E. CARPENTER.

